For me, it helped expand my cosmos by leaving things out and looking for alternatives.
Like, I found out about a world of legumes by going vegan. And earlier this year, I stopped eating wheat for health reasons, and only then started to appreciate the existence of millet, quinoa, amaranth, buckwheat etc..

I am probably still within the range of "usual" foods, all things considered, but at least I'm breaking out of a tiny subset of those...